package com.demo.gallery3d;

import android.content.Context;
import android.graphics.Camera;
import android.graphics.Matrix;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.Transformation;
import android.widget.Gallery;
import android.widget.ImageView;

public class GalleryFlow extends Gallery {
	   private Camera mCamera = new Camera();//相机类
	    private int mMaxRotationAngle = 60;//最大转动角度
	    private int mMaxZoom = -300;////最大缩放值
	    private int mCoveflowCenter;//半径值
	    public GalleryFlow(Context context) {
	        super(context);
	        //支持转换 ,执行getChildStaticTransformation方法
	        this.setStaticTransformationsEnabled(true);
	    }
	    public GalleryFlow(Context context, AttributeSet attrs) {
	        super(context, attrs);
	        this.setStaticTransformationsEnabled(true);
	    }
	    public GalleryFlow(Context context, AttributeSet attrs, int defStyle) {
	        super(context, attrs, defStyle);
	        this.setStaticTransformationsEnabled(true);
	    }
	    public int getMaxRotationAngle() {
	        return mMaxRotationAngle;
	    }
	    public void setMaxRotationAngle(int maxRotationAngle) {
	        mMaxRotationAngle = maxRotationAngle;
	    }
	    public int getMaxZoom() {
	        return mMaxZoom;
	    }
	    public void setMaxZoom(int maxZoom) {
	        mMaxZoom = maxZoom;
	    }
	    private int getCenterOfCoverflow() {
	        return (getWidth() - getPaddingLeft() - getPaddingRight()) / 2
	                        + getPaddingLeft();
	    }
	    private static int getCenterOfView(View view) {
	        System.out.println("view left :"+view.getLeft());
	        System.out.println("view width :"+view.getWidth());
	        return view.getLeft() + view.getWidth() / 2;
	    }
	    
	    
	   //控制gallery中每个图片的旋转(重写的gallery中方法)
	    protected boolean getChildStaticTransformation(View child, Transformation t) {  
	        //取得当前子view的半径值
	        final int childCenter = getCenterOfView(child);
	        System.out.println("childCenter："+childCenter);
	        final int childWidth = child.getWidth();
	        //旋转角度
	        int rotationAngle = 0;
	        //重置转换状态
	        t.clear();
	        //设置转换类型
	        t.setTransformationType(Transformation.TYPE_MATRIX);
	        //如果图片位于中心位置不需要进行旋转
	        if (childCenter == mCoveflowCenter) {
	            transformImageBitmap((ImageView) child, t, 0);
	        } else {
	            //根据图片在gallery中的位置来计算图片的旋转角度
	            rotationAngle = (int) (((float) (mCoveflowCenter - childCenter) / childWidth) * mMaxRotationAngle);
	            System.out.println("rotationAngle:" +rotationAngle);
	            //如果旋转角度绝对值大于最大旋转角度返回（-mMaxRotationAngle或mMaxRotationAngle;）
	            if (Math.abs(rotationAngle) > mMaxRotationAngle) {
	                rotationAngle = (rotationAngle < 0) ? -mMaxRotationAngle : mMaxRotationAngle;
	            }
	            transformImageBitmap((ImageView) child, t, rotationAngle);
	        }
	        return true;
	    }
	    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
	        mCoveflowCenter = getCenterOfCoverflow();
	        super.onSizeChanged(w, h, oldw, oldh);
	    }
	    private void transformImageBitmap(ImageView child, Transformation t,
	                    int rotationAngle) {
	        //对效果进行保存
	        mCamera.save();
	        final Matrix imageMatrix = t.getMatrix();
	        //图片高度
	        final int imageHeight = child.getLayoutParams().height;
	        //图片宽度
	        final int imageWidth = child.getLayoutParams().width;
	        
	        //返回旋转角度的绝对值
	        final int rotation = Math.abs(rotationAngle);
	        
	        // 在Z轴上正向移动camera的视角，实际效果为放大图片。
	        // 如果在Y轴上移动，则图片上下移动；X轴上对应图片左右移动。
	        mCamera.translate(0.0f, 0.0f, 100.0f);
	        // As the angle of the view gets less, zoom in
	        if (rotation < mMaxRotationAngle) {
	            float zoomAmount = (float) (mMaxZoom + (rotation * 1.5));
	            mCamera.translate(0.0f, 0.0f, zoomAmount);
	        }
	        // 在Y轴上旋转，对应图片竖向向里翻转。
	        // 如果在X轴上旋转，则对应图片横向向里翻转。
	        mCamera.rotateY(rotationAngle);
	        mCamera.getMatrix(imageMatrix);
	        imageMatrix.preTranslate(-(imageWidth / 2), -(imageHeight / 2));
	        imageMatrix.postTranslate((imageWidth / 2), (imageHeight / 2));
	        mCamera.restore();
	    }
}
